Better name for dictionaries.

Question

I'm designing a programming language, so I've been putting a lot of thought into the way base types are named.

"Dictionary" seems like a bad name for what dictionaries do. They aren't organized lists of words with their definitions; they don't deal with words, they don't with definitions, and they aren't lists. The only vague association they have with the word "dictionary" is that one performs "lookups" just as one does with a paper dictionary (which is as good an argument for calling them "phone books").

"HashTable" describes an implementation which may change.

"Associative array" (from JavaScript) gets points because "associative" is a good adjective for what it does, but loses points because "array" also describes an implementation, and worse, describes it inaccurately.

"Key/value pair set" seems most accurate but it too long to be useful (do you really want to type "KeyValuePairSet" every time?).

If we call a "key/value pair" an "association" we get "AssociationSet". That to me is the best but doesn't jump out at me as the right answer yet; it's still long and "set" still feels a bit wrong. "AssociationList" is worse ("list" implies ordering, which isn't there). I briefly considered just "Associations" but that sounds more like something I would name an instance rather than the class. "RelationSet" and "PairSet" are shorter but less descriptive (neither captures the fact that it's sort of a one-way relationship key to value; value to key is not meaningful within the context of dictionaries).

Any ideas what a better name for dictionaries might be?

Answer 1

"Map"?

You're mapping one value to another.

Answer 2

Essentially they are lists with a key indexer. You could call then KeyValuePairCollection.

Answer 3

You mention that you don't want to use "hashtable" because that ties it to a given implementation. But is that necessarily a bad thing? People developing code will care if your dictionary-like language construct has hashtable-like performance characteristics, and simply calling it a hashtable is the clearest way to communicate that.

However, if you really are going to have a general interface and then specific implementations (like how Java has the Map interface and then implementations like HashMap and TreeMap), then I agree with a paid nerd that "Map" is probably the best choice.

Answer 4

Map is a good and precise name, as suggested by a paid nerd.

I also like the name Table, that Lua uses.

Answer 5

Dictionary is the standard computer science term. Complaining that a real world dictionary isn't the same as the abstract data type is like complaining that a "heap" isn't literally a disorganized pile of stuff or that a "queue" doesn't involve people waiting in line to buy tickets. Many/most computer science terms are analogies.

That said, two other reasonable terms are "map" (as it is a mapping from keys to values) and "table" (hence, "hash table", a table implemented with hashing).

Java actually uses the term "map" (as well as "dictionary" -- Map was added later when they realized dictionary should have been an interface, but since the name was already used they had to come up with a new name.)

"Table" has the disadvantage that it can easily be confused with the database term.

Answer 6

Does "list" imply ordering? Not in the real world - shopping, list, to do list, laundry list.... None of those are ordered, they are just things written down as they occur to the list writer.

Inevitably any word you choose will collide with everyday usage and/or associations with specialist IT usage. So, if you really want a better word you'll need a fresh metaphor rather than trying to repurpose names from other languages. So how about Rack? Or IndexedBag? KeyPairStash?

Answer 7

Maybe it's my Perl background, but I prefer hash. # See, the symbol looks like what a hash looks like. If you have a hash of hashes. Just my subjective 2 cents. <shrug>

[Edit]

Think of a plate hash. The good stuff, not the canned. With chunks of potatoes, onions, peppers, maybe some corned beef. At first glance it looks like a big mess of delicious random food. But you can name the parts, upon examination. It's a type, weather you poor ketchup on it or lay some eggs on it. Now think of a Martha Stewart tray of vegetables. Everything is a nice list of vegetables. You can dip it in the ranch or humus or pile it on the plate. Hell, you can take some of the tomatoes and put it in the hash.

These are types. It's a way of organizing data that suggests what to do with it, but is separate from it, IMHO.

A map seems to me more of an action than a type. Here's how to eat the food or better yet how the food gets to your mouth.

In the end, it's just a name.

Answer 8

i feel that i woud choose something "Index" or "KeyedIndex", "KeyIndex"...

edit: haha DIYIndex! or maybe im getting the whole idea about dict's wrong?

Answer 9

In Python, dictionaries are officially the one and only example of mappings.

It's not hard to see that one may argue about what is reasonable to call "mapping", e.g. a function, in mathematics, is always a mapping. I'd imagine that we could call anything with a __getitem__() a mapping, which would also include sequence types, such as list.

However, note that there is an official definition (emphasis mine):

mapping: A container object (such as dict) which supports arbitrary key lookups using the special method __getitem__().

So, to answer your question, I would suggest either mapping or map.

Answer 10

As I understand the jinx is ...there is something ASSOCIATIVE in nature which has KEY VALUE relationshiop and we are looking for the word that brings out the same SENSE....so If were to word it I would call it AssociateKVMap ....but doesnt sound so cool ....so lets get more options i guess

Answer 11

The only vague association they have with the word "dictionary" is that one performs "lookups" just as one does with a paper dictionary (which is as good an argument for calling them "phone books").

How about lookup?

Answer 12

Map and hash have other meanings as well, which is slightly muddling.

I'm trying to think what you would call something like this in real life. Suppose you had a million movies to key and organize. You might find a specific movie's location by looking it up in the catalog or database. Libraries also use catalogs to organize books. Though there still may be some confusion with other uses of the term in computer science, just like table ( http://en.wikipedia.org/wiki/Database%5Fcatalog ), I think catalog or catalogue is an accurate and expressive term for a lookup table.

Answer 13

Good imho.

Assoc
Array
Dict
Hash
Index
KeyValue
Map
Table

Bad imho.

NSMutableDictionary
hash_map

Answer 14

AssociationCloud

MapCloud

Cloud because it is unordered. Nebulous.